This invention is directed to a technique for entering instructions, data and other information into a computer and, more particularly, to a user friendly computer input technique which does not require the use of hands and thus can be readily combined with another input technique, such as a keyboard, which does rely on hand usage.
The first and still most commonly used computer input device is the keyboard. When computers came into general use, typewriter keyboards were already familiar and the adoption of the friendly keyboard for this new purpose eased the transition into the world of computing. However, the keyboard has several limitations. Firstly, a familiarity and ability with it are required. As the use of computers has become more widespread, many users do not fit into this category. Secondly, handling certain tasks with a keyboard is much slower than with alternative input devices. Thirdly, multiple keyboard symbols representing certain instructions, for example, must be memorized since a large number of tasks must be performed by a limited number of keys thereby complicating the input operation and introducing a source of error. For these as well as other reasons, light pens, bar code scanners, sketch pads, touch screens, the mouse, and a host of other alternate inputs have been developed which are not only more user friendly than a keyboard, but also enable the user to perform feats previously not possible with a keyboard.
One of the easiest and most user friendly of these input devices is the touch screen. It permits the user to simply select from among a number of alternate commands, for example, which are displayed on the screen. All the user needs to do is simply touch the screen where the desired command appears. A position detector senses the location of the finger, inputs it to the computer which then compares it with the position of each diplayed command to determine which was selected. U.S. patents which disclose various approaches for implementing the touch screen include U.S. Pat. Nos. 3,764,813 to Clement et al, 4,247,767 to O'Brien et al, 4,267,443 to Carroll et al, and 4,301,447 to Funk et al.
Another user friendly input device is the mouse. It can be rolled on any surface to position a cursor on the screen. Buttons on the mouse can be used when the cursor is properly positioned to activate a desired function. One such technique is disclosed in U.S. Pat. No. 3,541,541 to Engelbari.
Both the touch screen and the mouse, as user friendly as they are, nevertheless cannot be considered replacements of the keyboard. The keyboard remains an essential component of any computer input system. Alternate input devices have certain advantages, but none can perform all the functions of the keyboard as well. Taking this as a given, it can readily be appreciated that many tasks require the cooperation of a keyboard and an alternate input device. For example, in word processing the cursor needs to be positioned precisely at the location where, say, an insertion is to be made; or in a spreadsheet the desired cell must be located so the necessary changes can be made. To locate the desired postion with a keyboard is time consuming. A touch screen or mouse can do it practically instantaneously. However, the operator must remove his hand from the keyboard, operate the alternate input, and then return to the keyboard to make the text changes. Removal of the hand from and return to the keyboard can be awkward and time consuming, particularly for a non-typist which, as mentioned above, is a category into which more and more computer users fit. Thus, the need exists for a user friendly input device which can be operated without requiring the operator to remove his hand from the keyboard.